jQuery.extend({

    handleError: function( s, xhr, status, e ){
        // If a local callback was specified, fire it
        if ( s.error ) {
            s.error.call( s.context || s, xhr, status, e );
        }

        // Fire the global callback
        if ( s.global ) {
            (s.context ? jQuery(s.context) : jQuery.event).trigger( "ajaxError", [xhr, s, e] );
        }
    },

    createUploadIframe: function(id, uri)
   {
         //create frame
            var frameId = 'jUploadFrame' + id;
            if(window.ActiveXObject) {
                  if(jQuery.browser.version=="9.0" || jQuery.browser.version=="10.0"){  
                       var io = document.createElement('iframe');  
                       io.id = frameId;  
                       io.name = frameId;  
                   }else if(jQuery.browser.version=="6.0" || jQuery.browser.version=="7.0" || jQuery.browser.version=="8.0"){  
                       var io = document.createElement('<iframe id="' + frameId + '" name="' + frameId + '" />');  
                       if(typeof uri== 'boolean'){  
                           io.src = 'javascript:false';  
                       }  
                       else if(typeof uri== 'string'){  
                           io.src = uri;  
                       }  
                   }  
               } 
            else {
                var io = document.createElement('iframe');
                io.id = frameId;
                io.name = frameId;
            }
            io.style.position = 'absolute';
            io.style.top = '-1000px';
            io.style.left = '-1000px';
            document.body.appendChild(io);
            return io
    },
    createUploadForm: function(id, fileElementId)
   {
      //create form  
      var formId = 'jUploadForm' + id;
      var fileId = 'jUploadFile' + id;
      var form = $('<form  action="" method="POST" name="' + formId + '" id="' + formId + '" enctype="multipart/form-data"></form>');    
      var oldElement = $('#' + fileElementId);
      oldElement.attr("name", "file");
      var newElement = $(oldElement).clone(true);
      // 修改旧元素的id
      $(oldElement).attr('id', fileId);
      // 将新元素的值赋空
      $(newElement).attr("value", "");
      // 将新元素放在旧元素的位置
      $(oldElement).before(newElement);
      // 将旧元素移动到目标表单
      $(oldElement).appendTo(form);
      //set attributes
      $(form).css('position', 'absolute');
      $(form).css('top', '-1200px');
      $(form).css('left', '-1200px');
      $(form).appendTo('body');     
      return form;
    },

    ajaxFileUpload: function(s) {
        // TODO introduce global settings, allowing the client to modify them for all requests, not only timeout      
        s = jQuery.extend({}, jQuery.ajaxSettings, s);
        var id = s.fileElementId;        
      var form = jQuery.createUploadForm(id, s.fileElementId);
      var io = jQuery.createUploadIframe(id, s.secureuri);
      var frameId = 'jUploadFrame' + id;
      var formId = 'jUploadForm' + id;      
        // Watch for a new set of requests
        if ( s.global && ! jQuery.active++ )
      {
         jQuery.event.trigger( "ajaxStart" );
      }            
        var requestDone = false;
        // Create the request object
        var xml = {}   
        if ( s.global )
            jQuery.event.trigger("ajaxSend", [xml, s]);
        // Wait for a response to come back
        var uploadCallback = function(isTimeout)
      {        
         var io = document.getElementById(frameId);
            try 
         {           
            if(io.contentWindow)
            {
                xml.responseText = io.contentWindow.document.body?io.contentWindow.document.body.innerHTML:null;
                    xml.responseXML = io.contentWindow.document.XMLDocument?io.contentWindow.document.XMLDocument:io.contentWindow.document;
                
            }else if(io.contentDocument)
            {
                xml.responseText = io.contentDocument.document.body?io.contentDocument.document.body.innerHTML:null;
                   xml.responseXML = io.contentDocument.document.XMLDocument?io.contentDocument.document.XMLDocument:io.contentDocument.document;
            }                 
            }catch(e)
         {
            jQuery.handleError(s, xml, null, e);
         }
            if ( xml || isTimeout == "timeout") 
         {           
                requestDone = true;
                var status;
                try {
                    status = isTimeout != "timeout" ? "success" : "error";
                    // Make sure that the request was successful or notmodified
                    if ( status != "error" )
               {
                        // process the data (runs the xml through httpData regardless of callback)
                        var data = jQuery.uploadHttpData( xml, s.dataType );    
                        // If a local callback was specified, fire it and pass it the data
                        if ( s.success )
                            s.success( data, status );
    
                        // Fire the global callback
                        if( s.global )
                            jQuery.event.trigger( "ajaxSuccess", [xml, s] );
                    } else
                        jQuery.handleError(s, xml, status);
                } catch(e) 
            {
                    status = "error";
                    jQuery.handleError(s, xml, status, e);
                }

                // The request was completed
                if( s.global )
                    jQuery.event.trigger( "ajaxComplete", [xml, s] );

                // Handle the global AJAX counter
                if ( s.global && ! --jQuery.active )
                    jQuery.event.trigger( "ajaxStop" );

                // Process result
                if ( s.complete )
                    s.complete(xml, status);

                jQuery(io).unbind()

                setTimeout(function()
                           {  try 
                              {
                                 $(io).remove();
                                 $(form).remove();  
                                 
                              } catch(e) 
                              {
                                 jQuery.handleError(s, xml, null, e);
                              }                          

                           }, 100)

                xml = null

            }
        }
        // Timeout checker
        if ( s.timeout > 0 ) 
      {
            setTimeout(function(){
                // Check to see if the request is still happening
                if( !requestDone ) uploadCallback( "timeout" );
            }, s.timeout);
        }
        try 
      {
           // var io = $('#' + frameId);
         var form = $('#' + formId);
         $(form).attr('action', s.url);
         $(form).attr('method', 'POST');
         $(form).attr('target', frameId);
            if(form.encoding)
         {
                form.encoding = 'multipart/form-data';          
            }
            else
         {           
                form.enctype = 'multipart/form-data';
            }        
            $(form).submit();

        } catch(e) 
      {        
            jQuery.handleError(s, xml, null, e);
        }
        if(window.attachEvent){
            document.getElementById(frameId).attachEvent('onload', uploadCallback);
        }
        else{
            document.getElementById(frameId).addEventListener('load', uploadCallback, false);
        }     
        return {abort: function () {}};    

    },

    uploadHttpData: function( r, type ) {
        var data = !type;
        data = type == "xml" || data ? r.responseXML : r.responseText;
        // If the type is "script", eval it in global context
        if ( type == "script" )
            jQuery.globalEval( data );
        // Get the JavaScript object, if JSON is used.
        if ( type == "json" )
            eval( "data = " + data );
        // evaluate scripts within html
        if ( type == "html" )
            jQuery("<div>").html(data).evalScripts();
         //alert($('param', data).each(function(){alert($(this).attr('value'));}));
        return data;
    }
})